Our information storage media has a surprisingly short shelf life. Optical disks of most types degrade within decades; magnetic media is more variable but even more fragile on average (see here and the linked pages). There are such things as archival disks, and a few really hardcore projects like HD-Rosetta, but they're rare. And then there's encryption and protocol confusion to take into account.

A couple centuries after a civilization-ending event, I'd estimate that most of the accessible information left would be on paper, and not a lot of that.

I don't know. Those objects make certain kinds of superstitions seem much more plausible.